Buggy code:
public abstract class TypeBinding extends Binding implements BaseTypes , TagBits , TypeConstants , TypeIds { public int id = TypeIds . NoId ; public long tagBits = 0 ; public static final TypeBinding wellKnownType ( Scope scope , int id ) { } public int kind ( ) { } public boolean canBeInstantiated ( ) { } public TypeBinding capture ( Scope scope , int position ) { } public void collectSubstitutes ( Scope scope , TypeBinding otherType , Map substitutes , int constraint ) { } public abstract char [ ] constantPoolName ( ) { } public String debugName ( ) { } public int dimensions ( ) { } public ReferenceBinding enclosingType ( ) { } public TypeBinding erasure ( ) { } public TypeBinding genericCast ( TypeBinding otherType ) { } public char [ ] genericTypeSignature ( ) { } public abstract PackageBinding getPackage ( ) { } public final boolean isAnonymousType ( ) { } public boolean isAnnotationType ( ) { } public final boolean isArrayType ( ) { } public final boolean isBaseType ( ) { } public boolean isBoundParameterizedType ( ) { } public boolean isCapture ( ) { } public boolean isClass ( ) { } public abstract boolean isCompatibleWith ( TypeBinding right ) { } public boolean isEnum ( ) { } public boolean isEquivalentTo ( TypeBinding otherType ) { } public boolean isGenericType ( ) { } public final boolean isHierarchyInconsistent ( ) { } public boolean isInterface ( ) { } public boolean isIntersectingWith ( TypeBinding otherType ) { } public final boolean isLocalType ( ) { } public final boolean isMemberType ( ) { } public final boolean isNestedType ( ) { } public final boolean isNumericType ( ) { } public boolean isParameterizedType ( ) { } public boolean isProvablyDistinctFrom ( TypeBinding otherType , int depth ) { } public boolean isRawType ( ) { } public boolean isReifiable ( ) { } public boolean isTypeArgumentContainedBy ( TypeBinding otherType ) { } public boolean isTypeArgumentIntersecting ( TypeBinding otherArgument ) { } public boolean isTypeVariable ( ) { } public boolean isUnboundWildcard ( ) { } public boolean isUncheckedException ( boolean includeSupertype ) { } public boolean isWildcard ( ) { } public boolean needsUncheckedConversion ( TypeBinding targetType ) { if ( ( this ) == targetType ) return false ; targetType = targetType . leafComponentType ( ) ; if ( ! ( targetType instanceof ReferenceBinding ) ) return false ; TypeBinding currentType = this . leafComponentType ( ) ; if ( ! ( currentType instanceof ReferenceBinding ) ) return false ; <START_BUG> ReferenceBinding compatible = ( ( ReferenceBinding ) ( currentType ) ) . findSuperTypeErasingTo ( ( ( ReferenceBinding ) ( targetType . erasure ( ) ) ) ) ; <END_BUG> if ( compatible == null ) return false ; while ( compatible . isRawType ( ) ) { if ( ( targetType . isBoundParameterizedType ( ) ) || ( targetType . isGenericType ( ) ) ) { return true ; } if ( compatible . isStatic ( ) ) break ; if ( ( compatible = compatible . enclosingType ( ) ) == null ) break ; if ( ( targetType = targetType . enclosingType ( ) ) == null ) break ; } return false ; } public TypeBinding leafComponentType ( ) { } public char [ ] qualifiedPackageName ( ) { } public abstract char [ ] qualifiedSourceName ( ) { } public char [ ] signature ( ) { } public abstract char [ ] sourceName ( ) { } public void swapUnresolved ( UnresolvedReferenceBinding unresolvedType , ReferenceBinding resolvedType , LookupEnvironment environment ) { } public TypeVariableBinding [ ] typeVariables ( ) { } }

Fix:
ReferenceBinding compatible = ( ( ReferenceBinding ) ( currentType ) ) . findSuperTypeWithSameErasure ( targetType ) ;